Sunday All Wood ARF Electro Parkflyer from Hobby Lobby

HI, I just wanted to start a thread on the Hobby-Lobby "Sunday All Wood ARF Electro Parkflyer" (http://www.hobby-lobby.com/sunday.htm). The plane is a neat mid-sized park flyer that was on sale from Hobby-Lobby last Wednesday for 50 bucks. I picked it up and am going to provide some information on this model. A fairly careful search revealed no useful information from the Web. If anyone has any thoughts, comments, or can point to an existing thread, I'd appreciate the guidance.

Anyway... this model looks remarkably like a mid-size version of the great planes super sportster. With a 44 inch wingspan it is larger than the mini-sportster and smaller than the regular e-powered super sportster. After a casual look, the wing appears to have a flat-bottom airfoil.

Hobby-Lobby calls for an Axi 2212/26 and 1300Mah lipos. I have neither of these. I'm going to be overpowering this model with a Justgofly.com 450T outrunner and Apex 2200 lipos. The motor weighs about the same as the Axi, but it will put out lots more power. I'll be running an 8x4 on this with an expected amp draw of 25 and a speed of approx 52mph and a thrust of around 28 ounces. The suggested Axi on a 9x6 will easily fly the plane at about 40mph with about 20 ounces of thrust for around 12 amps or so. So... I have given up efficiency but have saved the cost of a new motor.

The instructions call for 3 hs-55s. I am going to use a single hs-81 in the wing beacuse, frankly, the ailerons are long and I don't trust a 55 to handle the forces at 50mph. I'll use 55's on the small rudder and elevator though. The modification looks like it wil be painless.

I'll post more as I get more work done on the plane. Please feel free to discuss this pretty lil' bird. Thanks! -N_G

I had to go and get two of them, for $50 I just could not pass it up. I am going to fit it for an E-flite 480, with a TP 3 cell 2100. So far the trial fit for the TP is not going well, but I just have to do a little time with the Dremel about 1/8" above and below the first bulkhead. Looking at it, I feel that it is going to be a great flyer.

CG placement...did you guys get it to come out?

I balanced aft of the recommended point, and thought I could trim it out once airborn). I had already enlarged the firewall so the batt pack could fit as far forward under the motor, but it apparently was not enough. I can't see how they got it to balance with a stock setup!?!?

My maiden flight was almost a disaster.
I hand launched, and it lurched straight up with full power...(so much so that if I continued full power I think it would have done a loop) I think the pack may have slipped back making it even more out of whack CG'wise. I barely got it down in one piece.

My next solution is to change out the PJS900 (2.1oz) for the PJS 800 which is 1 oz heavier, (3.1oz)..that should help a lot in getting a better CG, and they have very similar power specs. I also need to secure the batt pack better so it doesn't shift on me. I was a little hasty in getting this in the air....almost lost the plane.

Even with the heavier PJS 800 it looks like I'll have to add 3/4-1 oz of weight to the nose to get it to balance. I have always managed to avoid adding weight..I hate to do that. With the added weight for balance, and the PJS 800 and 1800 lipo, the flying weight will come out to 23.8 oz.

I understand the "stock" setup is for a 1200mah lipo, but its lighter and would make the CG even more of an issue?

I'm anxious to hear others successful setups!
If I can get mine to balance....its going to rock!

From my experience, I'd have to say to build everything as far forward as possible. I don't think my problem had anything to do with wing incidence or elevator alignment. The next time I fly it the CG will be spot on where they recommend, and if I have pitch issues, I will look into the wing and tail layouts.

If anyones interested in photos, I'd be happy to show you what I've done.
I also found a nice 30 mm aluminum and black plastic spinner/collet type setup (like the white plastic one Hobby Lobby had on it)...really dressed it up.

I will weigh the parts when I get a chance. However, it is of interest to compare the weight listed on Hobby Lobbyís website with my measurement. Lets back-calculate the weight of the airframe + glue based on the flying weight listed in the advertisement.

So, subtracting 8.55 oz from 22 oz as listed yields an airframe weight of around 13.5 ounces. I have a crummy non-digital food scale that I will use to weigh the parts this evening.

I want to also note that this is my first Chinese-made wood ARF. I normally like to build my own but this was such a dealÖ. Anyway, it is clear to me that the builders paid a lot of attention to getting the covering to look nice and they sanded and treated the balsa wood under the covering to help with this. On the inside, though, there isnít much sanding. I would say that they rough-sanded the parts, if at all. So, thatís interesting to me. The laser cutting looks nice and there are a lot of holes to lighten the airframe. However, based on my first looks, there is no apparent hole for cooling air to exit the airframe. The underside of the fuselage is solid, though there are holes on the sides. I guess Iíll be cutting a trapezoid shape for cooling air to exit. I suppose this will have to be aft of the wing. Iíll also be cutting a small slit or hole into the fiberglass nose-cone to allow for air to enter. This slit will be up front below the propeller.

Oh! And one more thing. As noted above, the kit comes with a nice black spinner. Itís is a 2-screw jobber and looks nice. It is much nicer than the 30mm snap on one they suggest you buy with the kit. I bought it and it is now obsolete. Not only does the snap-on spinner not fit my prop adapters, its just plain cheesy lookiní. I guess it would work on the Axi mounts.

Hey RPM3, sorry to hear that your CG is off. I haven't gotten far enough along yet to know how that is all going to work. I noted that you did not use the landing gear. I was pretty impressed with the strength of the landing gear wire and installation. The wheels that are provided are too small for grass, so I went to a nice MPI type paprk flyer wheel. It looks like this: http://www.nesail.com/detail.php?productID=2559 .

I have the 2.5 inch version. Anyway, I'm looking forward to flying this thing off the club's grass field. I'm wondering if your cg would have been better if you used the landing gear? Please do let us know how it works out. N_G

Some photos

I'm not sure of what I wouldn't do, as the mods I made are insignificant as far as the weight goes (other than the battery). In fact, the suggested motor is about the same weight as the original PJS900 (at about 2 oz) that I started with, and the battery (1800 vs 1200) is 1.7 oz more, but it goes in front of the CG.....it baffles me that I'd end up tail heavy?

Now I'm using a PJS800 which adds an ounce to the nose, and I'm still slightly tail heavy?

But here are some photos for review.....also...gotta get the iron out on some of my wrinkles!

As a sidenote

I do plan on "cushioning" the front of the battery after I get the CG sorted out.
And I also was contemplating a cutout in the cowl for cooling, but hate to cut the nice fiberglass cowl. I don't think my motor and battery setup will get that hot....it doesn't even get warm on my other planes with a similar setup.

Wow. Can you elaborate on what exactly you did to your firewall? Mine looks nothing like that, its full of cooling holes and there is no good place to mount a motor stick. Please do let us know what you did. I'll have to see how mine balances. I've got a 2 ounce outrunner to use.... but I also have an insanely powerful 3.8 ouncer that is truely overkill (ts a Hyperion 3013-14, similar specs to a Hacker A30-16M :0) But if it needs the weight then so be it. We shall see. N_G

Apples and oranges maybe!?!?!?

I did not buy mine thru Hobby Lobby. I bought it from another ezoner, several months ago, and I bet its an older version?

Mine came with one small firewall hole, and I enlarged it.

The stick mount was in place, it had built in right and downthrust. I cut it slightly shorter so the aluminum motor mount would fit. The motor on the mount fit into the cowling hole for the shaft, dead center, like it was made for it.

So, we may be talking about the same plane, but an old version, and a new and improved one....like yours!?!?

Now I'm really curious to see and hear about all the HL types. Comparison photos would be interesting!

So, I wasn't all that far off when I back calculated an airframe weight of 13.5 ounces. I'm pretty happy with the way Hobby Lobby has represented the weight of this plane.

Now..... I completed the wing this evening. Glueing the airlerons in was a chore. The wood they used for the airleron was soft and I had some play around the torque rod. A squirt or two of thin CA seems to have cleared up the problem. Next, I mounted a HS 81 servo. The slot is for an HS 55 but I am glad I didn't use one because the strip airlerons are a bit tight and I'm not sure the 55 has the grunt to handle them. The 81 does just fine. I was forced to ditch the stock linkages. They are some very thin metal rods that have the worst threads I have ever seen. Calling them threaded rods is being generous. Its more like they have the ghostly impression of threads in them. Couple that with the cheap connectors and I was not a happy camper. I went with 2-56 rods with threaded ends and z-bends. I also had to use a fairly large arm to get decent surface throw. Those of you using hs-55s, please chime in here about your experience. I did have to hog out some balsa to fit the hs-81 but not much.

Then I started to look more closely at the motor mount area. This is driving me insane. First of all, I don't have the AXI backplate mount. I have what I thought was a clone of the AXI backmount. It turns out that the outer holes do not match up with the ones drilled in the motor mount cage. Ok, so maybe I wont use the backplate mount, I'll just bolt the motor to the provided holes in the motor cage. Well... that is fine, but it means you can NEVER get the motor off again without taking off the motor cage. There isn't enough room behind the motor cage to get an allen wrench in there to turn the screws. This means you have to install the motor and then build the motor cage and glue it all in place. Its a one shot deal. As far as I can tell there are no blind nuts provided to attach a backplate mount, and they don't come with the AXI backplate motor mount. So basically, you mount the motor and then can never remove it. Seems like a crummy way to install a motor.

Now, how to get around this? Well, i guess if I could find some 3 mil blind nuts, or maybe even 2-56 blind nuts, I could redrill the motor mount to accept the outer holes on my backplate mount. Seems like a pain in the butt. Whatever. If anyone can suggest a way forward, I'm all ears.

Even with that frustration, it is worth noting that the wing seated dead center on the fuse using the predrilled bolt hole and leading edge rod. I'm pleased about that. Also, I think that the wing and figuring out the motor/battery mount are the toughest parts. The tail feathers seem like they will go in easy with some epoxy and the mounts for the 55s are all ready to go. I'll call around to the LHS and see if I can't find some blind nuts.

Did anyone else notice that the instruction manual calls for a straight arm servo horn on the airlerons... but then later in the instructions, they call for differential in the up and down travel on the airlerons? I'm dying to know how they managed to do that with a straight horn.

Oh, and I trial fitted the Hypersion motor I have (its the same as a Hacker A30-16M). It is way to big to mount out on the motor cage. Were I to use that (and it would be extreme overkill) I would have to mount it on the firewall. This would likely be simple. If the 450T doesn't work out, then maybe I'll hack off the motor cage and mount the big guy up front.

I'll get more done tomorrow. Sorry I don't have pics, but my camera is on vacation out of state with the rest of the family. Maybe later this week after it comes back. Keep the information flowing! N_G

Anyway.... I got to spend some more time with the Sunday this evening.

I managed to mount the tail feathers and flying surfaces. This was simple with no problems encountered. The fit of the hinges was better on the tailfeathers than on the wing. So, I've mounted the wing and can see what the plane looks like. Its a pretty plane.

While the epoxy was drying on the tailfeathers I addressed the motor mount. As you will recall this part of the build was an issue for me. In the end, I decided that having the option to remove and service or replace the motor was important to me. I carefully drilled out the front of the motor cage to fit my JustGoFly.com backplate mount. This was easy. I then assembled and glued the motor cage with thin and thick CA. This was simple. Then I attached my motor to the axi-style backplate mount with screws and loctite, and then bolted the backplate mount to the motor cage using 2 sets of 3mm locknuts and machine bolts from extras I had laying around (they came out of the old T-maxx pile of parts). This turned out to be pretty easy, and I can now remove the motor at my whim.

I then installed the pushrods for the rudder and elevator. I screwed up.... here are several likely candidates for the exit points of the pushrods (oval cut-outs in the balsa). I opened one that isn't used on this design. Oh well, I guess some white zagi tape will cover that in the end. anyway, installing the control horns and the pushrods was simple. the stock rods were of marginally better quality than the airleron pushrods proveded. The threads were a bit better on these.

I haven't installed the servos yet. I've mail ordered some gear sets for them and they may arrive tomorrow.

Next I turned my attention to the canopy. I cut and sanded it to a nice radius. It does not 'fit like a glove' but itis acceptable. The instructions call for screws to hold it down. I would prefer a seal with glue, but I dont have RC-56. Maybe I can use aquarium sealent. Or maybe I will be bored by then and just screw in as needed. I would be more interested in the canopy if a pilot figure were included. but there isn't one.

I also addressed the battery area. I ran a velcro wire-tie (sometimes called a wire collector?) in there and that suspends the battery off the floor of the model. I don't know if I need any foam protection, as the battery pretty much can't move around in there. Its just about the same size as the battery compartment. In addition, I installed the magnet hold-down for the battery hatch. This was simple and I was rewarded with a solid "click" when I closed the hatch.

So whats left? Rudder and elevator servo installation, drilling and installing the landing gear hold-downs, installing a receiver, installing the cowl and the canopy, oepning a cooling hole aft of the wing and in the cowl, battery charging and flying.

Should be done by Saturday for a maiden. It is a pretty plane. The picture on the HL site does not show how well the cowl paint and the gold covering match. I know that mismatched cowl/covering colors freak people out, but this isn't as bad as the advert suggests.

Anyway, I''d love to hear of your progress or see your pics. Please don't be shy.

Another evening and some more work done. I replaced the gears in my old HS-55s and installed the elevator and rudder servos. This was more time consuming than I thought it would be. Getting the servo horns on the pushrods and then onto the servo in a centered position was a pain. Apparenly I have sausage fingers. Anyway, they are done and they look good.

I also added the landing gear. I like these gear, they are thick steel and have a nice wide stance. Perfect for a sport plane flying off grass.

I also installed the P35 ESC. No troubles there.

So that leaves: installing a receiver, installing the cowl and the canopy, iron out wrinkles, opening a cooling hole aft of the wing and in the cowl, CG check and flying. I'll do that tomorrow night. Saturday should be good weather for a maiden.